Re: [boost] [interprocess] boost::hash - different values for thesame input?

Subject: Re: [boost] [interprocess] boost::hash - different values for thesame input?
From: Daniel James (dnljms_at_[hidden])
Date: 2016-01-14 15:59:06

On 14 January 2016 at 04:54, Peter Dimov <lists_at_[hidden]> wrote:
> Daniel James wrote:
>
>> The reason why I originally wrote that note was because it can generate
>> different hash values when compiled for different
>
> platforms or architectures, e.g. a 32-bit executable might generate a
> different hash value to a 64-bit executable.
>
> Is this just because of pointers and floats, or are there other reasons?
> size_t hashing to different values perhaps?

Anything with a bigger range than size_t will have to, e.g. int64_t
will hash differently on 32 and 64 bit machines. Also, user hash
functions could be anything.